1. Field
The present application relates to improving drivability of a continuously variable transmission (CVT) for vehicles travelling at high elevations.
2. Description of the Related Art
A CVT generally can implement an infinite number of gear ratios within maximum and minimum values for the CVT. However, at low gear ratios and high engine speeds, too much torque may damage the transmission. A wide open throttle (WOT) guard, or other similar guards, prevents damage to the transmission by limiting gear ratios at predetermined engine speeds. The WOT guard is often predetermined or tuned at a base elevation.
At higher elevations, the thinner air affects the air-fuel ratio, which ultimately affects drivability and performance of the vehicle. Due to the thinner air, less torque is produced at higher elevations than at the base elevation. However, the WOT guard remains the same. In other words, the WOT guard provides greater performance reduction than needed at higher elevations because less torque is produced.
Thus, there is a need for a CVT vehicle which improves drivability at higher elevations by adjusting the WOT guard based on altitude.